Emergency telephone call and circuit therefor



Nov. 2, 1948. J. PALUMBO EMERGENCY TELEPHONE CALL AND CIRCUIT THEREFOR- Filed May 1, 1945 2 Sheets-Sheet 1 N 22 N 5& a) Y W IN VEN TOR NEW. 2, 1948. v J. PAL UMBO 2,453,032

EMERGENCY TELEPHQNE CALL AND CIRCUIT THEREFOR Filed May 1, 1945 2 Sheets-Sheet 2 IN V EN TOR;

Patented Nov. 2, 1948 EMERGENCY TELEPHONE CALL AND CIRCUIT THEREFOR Joseph Palumbo, Bronx, N. Y. Application May 1, 1945, Serial No. 591,274

Claims.

This invention relates to an improved telephone circuit and emergency signal control, and one of its objects is to provide a local customer station with means which will enable the central station to signal the customer when the receiver of the customers station is disengaged from the supporting hook.

Another object of the invention is the provi sion of a telephone receiver with a switch arranged to be operated by supplying excess current to the magnetic windings of the receiver, and a signal bell which is energized at the customer station, when the "receiver is supplied from a central control or switch with excess current.

With the above and other objects in View the .invention relates to certain new and useful con- The pivoted block I6 is equipped with a lateral magnetic finger I8, which is designed to be normally spaced out of contact with the side of the .pole end I, and is further provided with another lateral magnetic finger I9, which is normally spaced out of contact with the pole end 8', by the pressure of a curved cantilever spring 20, which is secured at one end to the insulation block I4, while the other end has sliding engagement with a metal strip 2|, which is mounted rigidly on the pivoted insulated block I6, this other end being slightly curled outwardly at a, so that the spring will engage the metal strip M with the minimum of friction, The curled inner end 20a of the cantilever spring bearson the metal strip 2| to one side of the pivot pin l1, so that the latstructions, combinations, and arrangements of parts, clearly described in the following specifia cation and fully illustrated in the accompanying drawings, in which:

Fig. 1 isa front elevation of the receiver, showfing the cap removed to. expose the pole ends of the magnets, the cap being broken away for convenience.

' Fig. 2 is a similar View, enlarged, showing the circuit for the receiver and emergency bell.

Fig, 3 is a diagrammatic view of the complete telephone circuit.

Fig. 4 is a diagrammatic view of a modified telephone circuit.

Referring to the accompanying drawings, which illustrate the practical embodiment of my invention, 5 designates a telephone receiver, which is provided with a case 6 of insulating material, and electromagnets I and 8, which include pole ends I and 8', which are normally engaged by the usual soft iron diaphragm 9. Thisreceiver is also provided with the usual retaining cap Ill, which is screw threaded on the case 6.

A plate I I, in the form of a crescent shaped body is mounted around the magnets l and 8, by means of the binding screws I2 and I3, theends of which project outwardly of the plate II. The inner semi-circular edge I I a of the plate is spaced from the magnets 17 and 8. 0n the binding post or screw I2 an insulating block I4 is mounted, and is retained in position by a nut I5, which is threaded on the post or screw I2.

An insulating block I6 is pivotally mountedon the plate I I by means of a pin I1, which extends through the block it between the ends thereof, and this pin pierces the plate I I at its inner end, so that the inner edge Illa of the block I B will be spaced out of contact withthe magnets I and 8 and their pole ends If and 8. I i

eral magnetic fingers I8 and I9 will be held out of contact with the sides of the pole end I and 8. It is understood that these pole ends project, outwardly, of the magnetic windings or coils, so

that there is ample room for the swinging motion of the lateral magnetic fingers I8 and IS.

The metal strip 2! is extended outwardly of one end of the block it and is provided on one side with a contact element Zia, which is normally spaced out of contact with the stationary contact element 22, which is mounted on the crescent shaped plate I l and is in electrical conducting connection with said plate I I.

The metal strip 2! is'engaged by the end of a screw 23, which is threaded on an insulation block 24, mounted on the plate II, which provides an adjustable stop for limiting the opening movement of the magnetic fingers I8 and I9.

The usual line wires 25 and 26 are connected to the windings of the magnets I and 8, with a current source or battery 21, and in circuit with the central station transmitter 28. The battery supply which normally flows through the magnets I. and 8, to maintain the necessary talking circuit, is insufficient to generate enough mag netism in the. magnets I and 8 to cause the projecting pole ends I and 8' to attract the lateral magnetic fingers I8 and IS, and as a result the pivoted switch block I6 and its metal strip 2I remain normally inoperative during the transmission of conversation over the talking circuit. I

The resistance offered by the spring 2!! to the pivotal movement of the block I5 and the strip 2 I, will be overcome by the charging of the magnets and t with current in excess of the current used in normal operation. To accomplish'this the spring 20 is connected to an additional circuit wire 29, at one end of the wire, and the other end of the wire is connected to the terminal 3 30 of the emergency bell 3|. The other terminal 32 of this emergency signal bell is connected by the Wire 33 with the wire 25, of the magnet I. An additional current source or battery 34 is provided which has its negative side connected to the positive side of the current source or battery 21. The positive side of the additional battery 34 is connected to a manual switch 35 of the central station by a. wire 36,. and is further connected by a wire 3? with the line wire 26. This line wire 26 is also connected to the plate I I, by a nut 38, which is threaded on the binding screw or post l3.

When the receiver is disengaged from the-usual supporting hook of the customer telephone set, the usual calling bell circuit is broken, and it is to subscribers transmitter 41, to wire Mi, and thence through wire 25 to the negative side of the battery 21.

Due to the fact that the energy of the battery 21 is only sufficient to operate the call bell, or the subscribers receiver and transmitter, and associated units of the included system, the emergency signal bell 3| will remain inactive during normal conversation use. of, the telephone. But should the subscriber fail to restore the receiver to its hook, at the end of the conversation, or leave the receiver off its hook for an indefinite period of. time, then the central station operator flow from both batteries 21 and '34, which are connected: to each other by the union line 34,

then impossible for the central station, with ex-- isting equipment, to sound any sufiiciently audible signal, to notify the customer that the receiver is not on its hook.

It, frequently happens, that acustomer will remove, the receiver from the hook ofi his set,. for the purpose of making anoutgoing: call or connection, and will bev called away from: the telephone, without completing. the connection, thus leaving thereceiver off its book.

Again a customer will bccalled to the telephone and will, release, the receive while awaiting a delayed connection, or'the end of an interruption, sothat. the: receiver will remain for a considerable-period of time from the supporting hook ofits'set.

Whenever a-telephone receiver is thus disengaged. from thereceiver-hook of its set, that par-- ticular customer telephone set is virtually isolatcdf'rom. the entire field telephone system, and itis; impossible for any person calling the iso latedtelephone to make connections to either signal the customer or to. engage in conversation.

In Fig. 3 I showa complete telephone circuit, and referring to. this figure a receiver hook is-indicated at W, pivoting at 40a. The linewire- 26 islcennectcd tothis-hook. Onewire M of a standand call bell-4 2,. is connected toa contact element Ma which is engaged. by the hook 4!), when the receiver is mounted on it orthe hook is otherwise. depressed. The other wire- 43- ot the-call bell is, connected to the-line returnwire-ZE, which is also connected to a primary coil, 44. A seconde ary. winding-or coil A5. is connected by awire 46 with. a contact element 460.; whichis engaged by the-hook. 4.0 when: the hook is in. its raised position, andthe hook in this position also engagesthe contact element 26aoftheline wire 26:.

When thesubscribers or customersstation is called, current flowsfrom the positive side; of bat.- tcrythrough the line wire 26, through the central? station switch 26a. through the central station: transmitter 28, to the receiver hook 43, tocontact 41a of wire 41, and throughthis wire to the call: bell; 412', and then. by return wire 43: to; the. return wire 255; back to the battery 21., at thexnegativeside thereof.

When the subscriber removes the receiver from the hook; the circuit through the call bell is, broken, in. the: usualmanner, by the hook being forced. upwardly by its spring, and electrical connection is thereby established between the hook and' the contacts 26a of the line wire 26 and 46a of a wire 46. Current will now flow from the battery 21 to the receiver 5, to the primary winding 44' tothe return wire 25' back tov the negative side of the battery 27. At the same time current will flow from the contact 46a, through the wire 4.5, through the secondary winding through the wire 31 to line 26, thereby by-passing the central station transmitter 28 and its switch 26a.

The excessive currentsupply will now flow from line-2.6. to the hook. 4.0,, and, thence through the Wires. 25, and 2.6; in the. manner above; described. But due to, the greater voltage of the. current supplied by bothv batteries 21. and 3.4 the energy ofi the. magnets l. and 8 willbe sufficient toattract the. magnetic fingersor armaturesr i8. and, |.9.',. and the switch strip 2| will close the circuit. with contact Z2, and. current will then. flow from. the wire 26. to. the. wire 3.! to the binding; post I3, to the metal. late. Ha, mounted on the plate IL, to contact 22, to contact 2l.a,. to. switchstrip 2L. to spring ZlLHthrOrtghv auxiliary wire 29 to. the emergencybell 3|, and thence b Wire 33 to. return wirev 2.5, and to. thenegative side. ofv battery 2]..

The auxiliary batter 3.4. is, therefore, never utilized except to. operatev the emergency signal hell. 3!, and the circuit through this bell is closed by supplying an excessive amount of currentora higher voltage current supply-to. the: receiver cir.- cuit, which thereby causes the receiver magnets to. attract. the. armature fingers i8, and L9,. and to close the. circuit through. the emergency bell 3t, thereby calling the subscriber to. the telephone.

In Fig. 4 I show a modified telephone. circuit. wherein. anemergency bell is. dispensed with, and the emergency callismade through. the. standard call, bell. 42.. In this. circuit, arrangement the: intermediate wire 29a: from the receiver 5, iSrCOn nected tora wire. 41.50; at. one end of: the call bell 42, a Wire 43:1: being connected to the. line. wire 25. A wire. 2.91: is providedwitha voltage switch 293,. which is normally inactive. But when the switch 35 is closed, and current. from both batteries 2'!v and- 34 is causedto flow through the feed wire 216-, then, the voltage switch 29s will close the line 29.72, and. current-Will flow'tothe call-bell 42,. thereby" signalling the subscriber; to respond:

Thevoltage switch 29s. is constructed: to.- operate onl withthe voltage current of both. batteiiies, but When'it does: close the line: 2921: and thereby energizes; the call bell, the sound thus generated by the call' bell will be of. greatepvolt: ume or intensity. than would normally pro:-- duced, sothat the subscriber would be thus; Sig?- nalled' that his receiverwas' off itshook.

It is understood? that various materials'may be used" in the construction ofthe parts; and that various changes and adjustments may be made in the detail construction of the-parts, their combination and arrangement, all within the scop 'oi the invention, as defined by the claims herein set forth. Having describedmy invention, I claim as newt? The combination witha telephone receiver having a calling circuit and a calling bell energized thereby and a talking circuit with a switch operated by the withdrawal of the receiver there from, of means for supplying current to the calling circuit to energize the calling bell or to the talking circuit when the receiver is disengaged from said switch, and connections between the calling circuit and the talking circuit for energizing the calling bell when the receiver is dis engaged from the said switch, said connections including means for supplying excess current to said talking circuit and a switch arranged to close the calling circuit when said excess current is supplied to the talking circuit.

2. The combination with a telephone receiver having a sound wave generating diaphragm and electro-magnets for acting on said diaphragm, a talking circuit for said electro-magnets, a calling circuit including a calling bell, a switch operated by the weight of the receiver for closing and opening said circuit last named, an emergency signal bell in circuit with the talking circuit, a switch operable by the electro-magnets of the receiver for controlling the circuit of the emergency signal bell, and means for supplying excess current to the talking circuit to increase the energy of the electro-magnets of the receiver, whereby said last-named switch will clos the circuit of said emergency signal bell to permit the calling of the subscriber when said firstnamed switch is in open position with reference to the calling circuit.

3. A telephone receiver having electro-magnets provided with projecting pole ends and pole faces, a diaphragm responsive to the pole faces, a talking circuit for said electro-magnets, a normally inactive emergency signal included in said circult, and a switch having a magnetic finger armature attractable by one of the magnet pole ends to close the circuit through the emergency signal when said talking circuit is supplied with current in excess of the current supply normally used to maintain the talking circuit active.

4. A telephone receiver having a pair of electromagnets with exposed pole ends, a switch arm pivoted adjacent to the magnets and provided with spaced magnetic finger armatures adapted to be attracted by the sides of the pole ends, a

spring for holding said finger armatures normally spaced from the pole ends, a switch contact engageable by the switch arm when said finger armatures are actuated, a talking circuit for said magnets, an emergency signal bell having one terminal in circuit with one wire of the talking circuit and the other terminal connected with the switch arm, and means for supplying current to i said talking circuit in excess of that required to maintain the talking circuit active, whereby the magnets will be supplied with excess energy and the finger armatures will be attracted t'oclose the circuit through the emergency signal bell.

5. A telephone receiver provided with a calling circuit and a talking circuit, aswitch engageable by the receiver for holding the talking circuit normally open and the calling circuit closeable at a distant point, an emergency signal bell having connections with the talking circuit and adapted to be inactive when said talking circuit is active, 1

means for charging the talking circuit with a current supply in excess of that required tomaintain thetalking circuit service active, and means carried by the receiver for rendering the said connections for the emergency signal bell operative when the talking circuit is supplied with such excess current supply. 1

i JOSEPH PAL UMBOF nnrnnnrions CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

